A. Field of the Invention
This invention relates to the field of hadron beams in synchrotrons designed for acceleration. More particularly, the present invention relates to a method for decelerating hadron beams using existing synchrotrons designed for acceleration. Even more specifically, the present invention relates to a method for decelerating antiprotons using existing synchrotrons designed for acceleration. More specifically, the present invention addresses the production of antiprotons; the collection and storage of antiprotons; the transport of antiprotons.
B. Background of the Invention
Hadron beams are typically accelerated using synchrotrons, cyclotrons, or linear accelerators. For example, at the Loma Linda proton therapy facility a synchrotron is employed once the protons are emitted by the ion source and pre-accelerated in a radio-frequency quadrupole (RFQ), while the Massachussetts General Hospital proton therapy facility employs a cyclotron. They accelerate protons up to a momentum of 0.73 GeV/c, which corresponds to the energy a proton needs to completely traverse a typical human chest cavity.
There are examples of synchrotrons specifically designed for deceleration of hadron beams. These include the LEAR and AD synchrotrons, both operated at the CERN particle physics laboratory in Geneva, Switzerland. These synchrotrons are used to perform scientic experiments with antiprotons.
A third category of synchrotrons, called storage rings, neither accelerate nor decelerate hadron beams to higher or lower momenta. Their purpose is to merely store the hadron beam at their original injection momentum.
Because the radius of curvature of a hadron beam traversing bending magnets is proportional to the beam momentum, and the cost of the synchrotron scales with its circumference, the synchrotron is designed such that the bending (dipole) magnets are at their maximum field strength at the maximum anticipated momentum. Therefore, storage rings always operate at the maximum strength of their magnets, while accelerating synchrotrons operated at maximum magnetic field strength only at the end of the acceleration process.
All mechanical and electrical systems have a finite dynamic range within which the components can operate. The same is true of synchrotrons. Due to limitations in magnetic material properties, power supply regulation, and radio frequency acceleration system frequency adjustability, synchrotrons traditionally are found to have a maximum momentum range of a factor of twenty. There is a great deal of literature devoted to this issue in the field of accelerator physics. This reality also explains why laboratories working in the fields of atomic, nuclear, and particle physics have accelerator chains composed of many synchrotrons. The Fermi National Accelerator Laboratory is an example, wherein there are three synchrotrons required to accelerate protons and antiprotons to a momentum of 950 GeV/c for particle physics research. The maximum momentum range of any of these synchrotrons is a factor of 17.